On account of the increasing complexity of applications in the area of informational motor vehicle electronics, which in the meantime can be referred to as multimedia, new concepts for networking different devices have become necessary.
By way of example, at least car radio, mobile telephone and navigation system are intended to be able to communicate bidirectionally with one another, so that, e.g. the music reproduction of the car radio is muted and the mobile radio link is operated via the radio loudspeakers if the user would like to use the telephone. It is evident, however, that this is only a very simple application and the multimedia networking of the on-board electronics is subject to virtually no limits for satisfying customers' demands.
In order to meet these complex requirements, optical data transmission has gained acceptance in the meantime for these connections in the area of automotive engineering. A new standard called MOST® has been specifically developed in this regard. The specifications of the MOST® standard have been published inter alia as “MAMAC Specification” Rev 1.0, November 2002, Version 1.0-00 under http://www.mostnet.de/downloads/Specifications/MAMACSpecification_IV0-00.pdf and under http://www.mostnet.de/downloads/Specifications/Physical%20Layer%20 Specification/010223 WgPhy Drawings.zip. Reference is hereby made to the specifications on which the MOST® standard is based and their contents are incorporated in their entirety in the subject-matter of this disclosure by reference.
A compact type of optical MOST® connectors comprises electro-optical converters fixed to the connector on the rear side. Said connectors contain internally short waveguide sections for the connection of the converters.
It is known to fit an electrical shielding to the housing of the connector in order to protect the sensitive electro-optical converters against electrical discharges when the connector is picked up e.g. by a person. For this purpose, such shieldings are typically applied to the outside of the connector housing and more or less surround the region of the electro-optical converters in the manner of a cage. It is also known to provide the converters with their own metallic housings.
However, these shielding measures, under certain circumstances, do not provide adequate protection against electrical discharges. On the other hand, an electrical discharge in the form of a “flash of lightning” on the electro-optical converter can destroy the latter, which entails a costly repair, typically even the complete replacement of the connector.
In the area of automotive engineering, for example, where such connectors have to withstand the requirements of the tough garage environment, it has been shown that the known protection measures are often inadequate.
In particular, this type of shielding only protects the sensitive components against a discharge externally. However, it provides no protection against a discharge internally in the connector.
From European Patent EP 0 267 074 B1 a protection device for a fiber optic connector against electromagnetic perturbations and electrostatic discharges is known. The document teaches to provide a metal screen between two housings of opto-electronic component and a plate with a metal grounding layer. The metal screen is pierced with apertures for the passage of sockets of the components' housings.
From U.S. Pat. No. 5,499,311 to DeCusatis a receptacle for connecting parallel fiber optic cables to a multichip module comprising a conductive jacket disposed around a receiving body of the connector is known.
From European Patent Application EP 0 921 425 A2 a fiber optic connector with a conductive shield formed around the connector is known.
Disadvantageously, these devices also merely protect against influences from outside.
However, in the context of the present invention, it has been found by the inventor that an electrical flashover to the optical fiber sections inserted in the connector can take place and can be forwarded via said fiber sections to the electro-optical converters if, by way of example, an electrostatically charged person inserts a finger into the interior of the connector and touches or just comes close to the optical fiber sections.
This risk may on first impression appear to be insignificant since the optical fibers are composed of plastic, having an extremely low conductivity.
However, even the conductivity of the plastic fiber section e.g. at its surface may suffice if the flashover voltage is high enough.
This risk occurs in particular in the case of MOST® connectors, as the fiber section in these connectors is inserted into a plastic sleeve. Furthermore, in the area of automotive engineering the connector may be exposed to moisture that may collect between the fiber section and the sleeve and may increase the conductivity by orders of magnitude. This considerably increases the risk of a voltage flashover to the converter.
All in all the previously known solutions in this regard are subject to improvement. On the other hand, in this competitively contested market, even apparently slight qualitative and/or cost-related advantages often suffice to obtain a decisive lead over the competitors in the market.